CVE-2026-104423

Name of the Vulnerable Software and Affected Versions Zebra (zebrad) versions prior to 6.2.1

Description An asymmetric resource consumption issue allows unauthenticated peers to stall block verification. This occurs when attackers flood the shared unprioritized Halo2 verification queue with zero-fee V6 mempool transactions containing zero-filled Orchard and Ironwood proofs. Halo2 is a proof system used for verifying transactions without revealing private data. This activity causes nodes to fall behind the chain tip.

Recommendations Update Zebra (zebrad) to version 6.2.1 or later.